The present invention relates to a frame structure of an automotive vehicle, and in particular, relates to a frame structure of an automotive vehicle equipped with a so-called radar frame, in which a cabin is supported by a cab-mount bracket which is provided on a vehicle outward side of a front portion of a pair of side frames which extends in a vehicle longitudinal direction.
Conventionally, the frame structure of an automotive vehicle equipped with the radar frame, such as a cab track, which comprises the cab-mount bracket to support the cabin which is provided on the vehicle outward side of the side frame, is known. Specifically, the cab-mount bracket is attached to a side face (outer side face) of the vehicle outward side of the side frame which has a substantially quadrilateral cross section. The cabin is mounted on an upper portion of the cab-mount bracket. Japanese Patent Laid-Open Publication No. 2002-205662 discloses such a frame structure of an automotive vehicle.
However, a conventional frame structure of an automotive vehicle has a problem in that the cross section of the side frame changes greatly at a vehicle frontal collision. Specifically, when an impact force acts on the side frame at the vehicle frontal collision, a shear force occurs at the cross section of the side frame in an elevation view, so that the cross section of the side frame may have a shear deformation. Particularly, in case the side frame is formed by a couple panels which are joined together, the shear force may concentrate at a joining portion of the panels.